Lathe



N. F. FRETTER.

LATHE.

APPLICATION FILED APR. 22 1911;.

1,40 ,997, Patented Mar. 7, 1922.

l 4 sums sm-zu I. 2% 160 N. F. FRETTER.

LATHE.

APPLICATlON FILED APR. 22; 1918.

Patented Mar 7, 1922.

4 SHEETS-SHEET 2.

N F. FRETTER.

LATHE.

APPLICATION FILED APR. 22 IBIS.

1 408 997; Patented Mar. 7, 1922.

. t 4 SHEETS-SHEET 3- 8 161 .9691 90 7 61, 69:?40 w :0 g o N. F.FRETTER.

LATHE.

APPLICATION FILED APR. 22, 1918.

Patented Mar. 7, 1922.

r 2 w w ,5 w a m m M I 7 111/ r/l J U 7 UNITED? STATES PATENT OFFICE.

NATHAN F. FRETTER, OF CLEVELAND, OHIO.

LATHE.

Original application filed August 18, 1917, Seria1 No. 186,859.

Specification of Letters Patent.

22, 1918. Serial No. 229,896.

To all to 710m it'mag concern Be it'known that I, NATHANLF."Fnnrrnn,

a citizen of the United States, residing at Cleveland, in the county ofCuyahoga and State of Ohio, have invented a certain new and usefulImprovement in Lathes, of which the following is a full, clear, andexact description, reference being had to the accompanying drawings.

This invention relates to improvements in lathes of the class disclosedin my former application, Serial No. 186,859, filed August 18, 1917, andwhereof this application is a division.

As in the former case, the present machine is designed to finish whatare known as yoke ends, although the invention is applicable to machinesfor finishing various other kinds of articles, as will readily be seenfrom the following discussion.

The main object of my present invention is to simplify and accordinglycheapen the construction of the embodimentwhich constitutes the subjectmatter-of my former application above referred to; and in general, itmay be defined as consisting of the/combinations of elements set forthin the claims annexed hereto and illustrated in the drawingsaccompanying and forming a part hereof and wherein Fig. 1 is a plan viewof a turret lathe constructed in accordance with my present invention;Fig. 2 is a vertical transverse section on line 2 2 ofF 1, looking inthe direction of the arrows; Fig. 3 is a horizontal section on the line3-3 of Fig. 9., looking down; Fig. 41 is a section substantially on thelines 1 lof Figs. 1 and 3; Figs. 5, 6, and '7 are details of one of thechucks or. workholders, the last mentioned being a section on line 77 ofFig. 5: Fig. 8 is a sectional detail on line 88 of Fig. 3; Fig. 9'is aperspective View of a yoke end, the article my present machine isdesigned to finish; Figs. 10, 1.1 and 12 represent, successively, thevarious operations in the order in which they are performed on the yokeend by my machine; and Fig. 13 is a sectional detail on the line 13-13of Fig. 1.

The housing 1 of the machine is generally cylindrical in form and has abase flango 2. At its upper end it has an upwardly opening channel 3within the bottomot which and at suitable distances thercabout aresupported rollers etupon pins 5 which have their ends supported withinthe opposite side walls of the channel. The top of the housing. is openinside the channel, and shown as formed integral with the outer wall ofthe channel is a trough 6 which has communication, through a tube 7 witha drain basin 8, the latter being illustrated as formed integral withthe rear side of the machine. lVhile I have said that the housing isgenerally cylindrical, in form, it is made straight at its rear sidebelow its top to adapt it to mechanism located in that vicinity, andpresently to be introduced.

The turret 10, which is in the form of a ring, is supported within thechannel 3 upon the rollers 4 so as to rotate freely. The lower outerface of the turret is provided with gear teeth 11 which extendcontinuously throughout its circumference, the teeth being entirelyconcealed by the outer wall of the channel 8. 90 apart about the turret,its upper surface is radially grooved v at 1 1- to receive in thesidesof each groove, plates 15, and the opposed edges of these platesare formed to produce between them a dove-tail guideway within which isslidably retained the lower portion of a chuck or workholder 16.

In Figs. 5, 6 and 7, where the chucks or workholders 16 are shown indetail, it will be observed that the same is made up of an upper block18 and a lower block 19, which are hinged together on pins 20, a pinbeing located on each side of the vertical center and spaced therefromto leave the central portion of the chuck unobstructed, the lower blockhaving a dovetail extension 21 for guidance within the dovetail grooveahovedescribed. A roller 22 is set within therear of the block 19, and aroller in the front face thereof. A cavity "25 is formed in the front ofthe blocks 18 and 19 and is divided substantially equally between thetwo, the cavity opening "through the rear of the blocks between theirhinged connections. A hardened jaw 27 is clamped within each block byscrews 26, and each jaw has a recess 28. These recesses are adapted toreceive the shank y of a yoke Y so that the bosses y/ of the yokeproject beyond the front of the chuck, while the end of the shank isexposed through the opening in the rear of the chuck. A fork 3O fitsdown V trated in Fig. 11.

over the block 18 and has its side branches pivotally connected theretoby means of the screws 31, the branches extending down over the sides ofthe block 19 to receive within their notches 32 the anti-frictionrollers 23, carried upon screws 34 which pro ject from the sides of theblock.

The notches 32 are of such shape as to produce a camming action as theirlower sides engage and ride beneath the rollers'33 ator when he wishesto open or close the.

chuck.

.In Fig. 11 have'designated, by the letter A, the. station at which the,articles to be finished are inserted into and removed from the chucks.ently to be described the turret is rotated intermittently tl'u'ough909, always in one direction. .At the station designated B, in Fig. 1,the first step of the operation is performed. to wit, the drilling ofthe shank y of the yoke, such step being illustrated in Fig. 10. At Cthe circular faces ,Of the bosses :y' are finished, such constitutingthe second step in the finished operation, as illus- At D, the bore ofthe shank is tapped or threaded and the bosses are drilled as indicatedin Fig. 12, which represents the third and final step of the finishingoperation. Each chuck arrives at station B at the outer edge of theturret 10 and remains in. such. a position during the performance of thefirst step of the operation. As the chuck advances toward the station(l, the roller 23 in the front face of the block 19 engages the edge ofa cam 5 0 which shifts the chuck inward. The cam is secured by screws 41to the side of the channel 3 and projects upward and over the turret,the depth of the cam being sufficient to move the chuck to the innerside of the turret ring. During the cutting operation. which isperformed at station C, the chuck is advanced toward the outer edge ofthe turret by mechanism which will presently be described and intooperative relation to the cutters, the movement being sufficient toproject the bosses completely past the edges of the cutters. Any furtheroutward movement of the chuck necessary to bring it to the extreme outeredge of the turret is ac complished by the cam 43 which is secured tothe inner Wall of the channel 3 and rises upward and overhangs the rearside of the turret, the edge of the cam. being arranged to engage theroller 22 in the rear of the block 1.). The chuck isheld in thisposition by cam 43, during the operations performed to the inner side ofthe channel 3.

By means of mechanism pres- "shaft extends transversely of the housingmeshes with a gear 61 that is fixed to the shaft 55. The shaft 55hasalso secured to it a worm 62 which meshes with a worm wheel 63 keyed to'a central vertical shaft 64:. This shaft is journaled within a boss 65of a casing 66. enclosing the worm wheel,

and in a bearing 67 that is shown as made a part of a brace 68whichebridges the upper end of the housing and has its ends secured Aearn 1 and is supportechby suitable bearings 72 and 73, directly beneaththe lower end of the vertical shaft or and is driven therefrom throughthe mitre gears 74 and 75 which are carried, respectively, by the shafts(it and 70. The casing 66, above referred to, is supported and spacedfrom the sides of the housing by arms 76.

The turret 10 is driven by a pinion 8O keyed to the upper end of theshaft 81 supported within brackets 82 extending rearwardly from thehousing 1. The shaft 81 has a bevel gear 85 secured to its lower end,and this gear meshes with asimilar pinion 86 that is fastened to theright hand end (as viewed from the front of the machine) of a sleeve 87,mounted on a shaft 88, supported in a horizontal position by brackets89,- carried b the rear of the 'housingrl. The end of the sleeve 87opposite the pinion 86 has fastened to it a clutch member 90 for 91, andits opposite end isprovided with a roller 97 which traverses the groove98 of the cam 9.2. The groove of the cam is so shaped as to engage theclutch member 91 with the member 90, and thus move the turret; twiceupon each rotation of the cam, and also to permit a dwell of the turretintermediate its movements of sufficient duration to allow for theoperation of the tools. The

shaft 88 receives its power from the main driving shaft 51 through agear 100, secured to its left hand end, and meshing with the gear 0 onthe shaft 51,

Thi s I have already explained how the turret is intermittently moved(each movement extending through 90), and it may be tem the channel3,,the plunger having a socket at its lower end which receives the upperend of a rod 107 that is guided within a bracket 108 secured to the sideof the housing. A yielding connection is provided between the plungerand rod 107 by a spring 110 that is confined between the lower end ofthe plunger and a nut 111 adjustable along the rod, the separation ofthe rod and plunger being limited by a pin 112 which.

extends through a slot in the lower end of the plunger. The rod is heldagainst rotation within the bracket 108 by a set screw 113 that isthreaded through the wall of the bracket 108 and enters a longitudinalgroove in the rod. This is for the purpose of maintaining a roller 115carried by the lower end of the rod in proper relation to a cam 1.16which is fastened to the shaft 70. It may be explained that as theturret approaches its period of rest, the care 116 'ele Vates theplunger into contact with the bot tom of the turret so that when onerecess 118 of a series wherewith the bottom of the turret is provided isbrought into register with the plunger, the plunger is projected intothe recess by the spring 110.

I shall now describe the mechanisms that are located at the respectivestations B, O and D. Rising from the inner side of the channel 3, atstation E, is a bracket 120 that has a horizontal boss 121 at its upperend within which is journaled a-spindle 122, the boss being divided nearits middle for the accommodation of a sprocket wheel 123 that is splinedto the spindle. Atits forward end the spindle is provided with a toolchuck .124, which may be of any approved type, and within which isclamped the shank of a drill 125. The sprocket 123 is driven, through achain 127, from a sprocket wheel on the main shaft 51.

Aplate 133, having an aperture at its cen ter which is adapted to beplaced over the drill 125 so that the plate may engage the (illllCiC124, has flexible members 135, such as 7 light weight cables, attachedto its ends, the

flexible members or cables extending rearwardly over sheaves 136 thatare supported upon opposite sides of the rear portion of the boss 121,and having a weight 137 attached to their lower ends which tends to drawthe spindle inwardly. The rear end of the spindle contains a ball, orother anti-friction device 138 which is adapted to engage the dependingend of a slide 140 (see Fig. 2) that is mount ed for reciprocationwithin a guideway in the upper side of the boss 121. The slide,

in turn, is provided at its inner end with a roller 141 arranged to ridethe periphery of a cam 142 that is secured to the upper end of theVertical shaft 64, the cam being shown as one of a stack of threeresting upon a flange 143 of the shaft and held thereagainst by anut 144that is threaded upon the reduced end of the shaft. As the cam is 1'0tated to the right, as viewed in Fig. 1, it will, through theintervention of the slide, advance the spindle and consequently thedrill 125 forwardly to bore the shank of a yoke Y that is carried by achuck then located in front of the drill.

A bracket 148 rises from the inner wall of the channel 3 at a station Cand has a boss 149 at its upper end within which a plunger 150 isreciproc-able, the rear end of the plunger being provided with ananti-friction member 151 which is adapted to be engaged by the dependingend of a slide 152 that is reciprocable within a guideway 153 in theupper side of the boss 149 (see Fig. 4). This slide has an anti-frictionroller 154 that bears against the periphery of the upper cam 155 of theaforesaid stack, the cam surface being so inclined as to move the slideand plunger outward as the cam rotates toward the right. A spring 156,which has one of its ends anchored to a post 157 supported by the boss149 and its opposite end fastened to a pin 158 which is attached to ahead 159 that is applied to the forward end of the plunger, tends toretract the plunger with the slide 152 and hold the roller 154 thereofin engagement with the cam. The head 159 engages the rear side of achuck located at station C to move the chuck outwardly across theturret.

Supportedvertically within suitable bearings 160 (one of which isrevealed, in Fig. 4) that extend rearwardly from the housing of themachine is a shaft 161 which has secured to it above the plane of theturret a series ofof the shaft 161 is journaled within a block 163 whichhas an adjustable dovetail connection with a riser 164 extendin upwardfrom the housing. A bevel pinion 165 is secured to the lower end of thecutter shaft 161 and meshes with a similar pinion 166 that is fastenedto the before mentioned shaft 88 beyond the right hand end of the sleeve87.

At station D a bracket 170 rises from the inner side of the channel, 3,this bracket being quite similar to the one located dia metricallyopposite. The bracket 170 has a boss 171 at its upper end within which aspindle 17 2 is slidably mounted and the boss is divided at about itslongitudinal center to accommodate two pulleys 173 and 174 that aresplined to the spindle, the spindle 7 having a chuck 17 at its outer endwithin described.

which a tap 176 is supported for threading the bore in the shank of theyoke that is clamped in the adjacent chuck or work holder. A plate 177is perforated at its center so that .it may be passed over the tap andbrought to bear upon the face of the chuck 1.7 5, the ends of the platehavingfiexible members or cables 178 secured to its op posite ends whichpass rearwardly over sheaves 179, the flexible members having connectedto their depending ends a weight 180 which tends to draw the spindleinwardly to bring its inner end'181 into en gagement with the peripheryof the lowest cam 182 of the aforesaid stack. This cam is of such shapeasto initiate an advance movement of the tap 176 and permit of itsretraction during a half rotation of the cam.

A spindle 185 is reciprocably supported in the upper end of a bracket186 which is secured to and rises from the outer side of the trough 6adjacent the tapping mechanism just described; and the spindle 185 hasachuck 188 at its lower end within which is clamped the shank of a drill189, the drill being supported near its lower end by a guide 190 thatextends outward from an adj acent part of the bracket 186. The drill isthus supported in a position to bore the cylindrical bosses of the yokethat is clamped within the adjacent chuck.

A pulley 195 is splined to the spindle 185 within the head. of thebracket 186 and is driven, through a belt 196, from a pulley 200 that iscarried by the upper end of a shaft 201 supported within the brackets202 that extend from the housing in the vertical plane of the main driveshaft 51. The-shaft 201 has a bevel pinion 205 secured to its lower endwhich meshes with a bevel pinion 206 that is fastened to the right handend of the main shaft so that thedrill 189 is constantly driven from themain shaft through the transmission mechanism just An arm 210 extends tothe rear and upward from the upper end of the bracket 186 and haspivoted to its outer end a lever 212. This lever is forked at itsforwardend to embrace a shifting collar 213 to which it is pivoted, andthe collaris rotatably mounted upon the upper end of the spindle 185.The rear end of the lever has connected to it an adjustable link 214that is guided within a bracket 215 carried by the housing 1. The linkis shown as having a roller 216 at its lower end that bears upon. a cam217 secured to the right hand end of the cam shaft 7 0 where itprotrudes beyond the housing.

I have mentioned the fact that pulleys 17 Sand 174 are splined to thetap spindle 172, and I shall now explain how these pulleys are drivenalternately in opposite directions to drive the tap on its cutting ex-,pedition andthcn reverse its direction of rotation to withdraw it. Onthe right hand end of the shaft 55 there is loosely mounted a: gear 220which has keyed to the inner end of its sleeved hub a pulley 221 locatedsubstantially in the vertical plane of the pulley."

173, (see Fig. 3). Another gear 222 is loosely mounted upon the hub ofthe gear 220 and has a pulley 223 formed integral" forth from the pairof pulleys 173 and 221,

to the pair 174 and 223 by automatic shifting mechanlsm as follows: Thebelt 227 is embraced by a fork 230-formed on the end of a lever 321 thatpivoted at 232 to a bracket extending from the worm-wheel casing 66, andthe end of'the lever opposite the fork is shown as having a roller233which traverses the groove 234 of a cam235 carried by the cam shaft70. The operation of this belt shifting mechai'iisn'i is obvious.

An oil pump 240 is located within the basin 8 and is driven by a belt241 from a pulley 242 on the main drive shaft, and operates toelevatealubricating solution from the basin through the pipe 243'to adistributing pipe 244 which hasbranches for deliveriug the lubricant tothe various tools.

Any chips which accumulate upon the turret to the rear of the chucks,through the drilling operation at station B, are forced from the turretby the backward movement of the chuck, as it is engaged and shiftedinward by the'cam 40, and into a chute 246 horted by the vertical shaft64' is double so that an outward movement of its corre-' sponding slidewill take place upon each half rotation of the shaft 64. I do notconsider these proportions essential, however, for it is obvious thatthe numberof-movements of these slides'may be more or less with respectto the rotation ofthe shaft without deviating from the purpose of theinvention.

Having thus described my invention, what I claim is i 1. In a machine ofthe character set forth, the combination of a plurality of movablysupported tool carriers having cam engaging portions in individualplanes, dissimilar tools carried by the respective carriers, and amoving element common to said carriers and having individual cams in therespective planes of the aforesaid cam engaging portions and arrangedfor cooperation there with, each cam distinguishing in profile from theothers according to the requirements of tool wherewith it is associated.

- 2. In a machine of the character set forth, the combination of meansfor supporting a plurality of pieces of work at a given elevation, aplurality of tool carriers supported at the same elevation, the work andcarriers being relatively movable to present each carrier successivelyin operative relation to the successive pieces of work, the carriershaving cam engaging portions in individual planes, dissimilar toolscarried by the respective carriers, and an actuating element common tosaid carriers and having indi- 'vidual cams in the respective planes ofthe aforesaid cam engaging portions arranged to cooperate therewith tomove the carrier toward the work, each cam distinguishing in profilefrom the others according to the requirements of the particular toolwhere with it is associated.

3. In a machine of the character set forth, the combination of a centralactuating device,'a series of tools, work holders movable in an orbitabout said device and in operative relation to the tools, elementsmovable to create relative movement between the work holders and toolseach having a cam engaging part out of the plane ofthe correspondingparts of the other elements, the actuating device having an individualcam in the respective plane of and for cooperation with the cam engagingpart of each element, and mechanism for operating the actuating member.

4:. In a machine of the character set forth, the combination of acentral actuating device, a series of tools, work holders movable in anorbit about said device and in operative relation to the tools, elementsmovable to create relative movement between the work holders and tools,each having a cam engaging portion out of the plane of the correspondingportions of the other elements, the actuating device having anindividual cam in the respective plane of and for cooperation with thecam engaging portion of each element, and mechanism for moving the workholders intermittently and positioning them in operative relation to thetools, while rotating the actuating device continually in one direction.

5. In a machine of the character set forth, the combination of asupporting structure, an annular turret movably sustained thereby, ashaft supported byv the structure in a vertical position centrallyof-said turret, workholders carried by the turret, tools supported bythe structure intermediate the shaft and work holders, a mover for eachtool having a cam'engaging portion that is out of the plane of thecorresponding portions of the movers of the other tools, cams mountedupon the aforesaid shaft, one cam in the plane of the cam engagingportion of each toolmover, driving means for the tools, and drivingmeans for the shaft.

6. In a machine of the character set forth, the combination of asupporting structure, an annular turret movably sustained thereby, ashaft supported vertically by said structure and centrally of theturret, workholders carried by the turret, brackets rising from thestructure between the turret and shaft, tool carrying spindles journaledwithin said brackets and capable of longitudinal movement therein, a camengaging member associated with each spindle, the. members of thevarious spindles occupying different planes, a plurality of cams carriedby the aforesaid shaft, one in the plane of and for engagement with eachof the aforesaid cam engaging members, said cams serving to advance thetool spindles toward the work holders, means tending to retract thespindles, driving means for the spindles, and driving means for theaforesaid shaft.

7. In a machine of the character set forth, the combination of asupporting structure, a turret movably sustained thereby, work holderscarried by the turret, a shaft supported by the structure in a verticalposition and centrally of the turret, tool carrycam shaft, drivingconnections between the cam shaft and the vertical shaft, an operat inglever for the aforesaid clutch, and a pain on the cam shaft foractuating said ever.

V 8. In a machineof the character set forth,

the combination of a supporting structure,

a turret movably sustained thereby, work holders carried by the turret,a shaft supported by the structure in a vertical position and centrallyof the turret, tool carrying spindles supported by the structure, camscarried by the vertical shaft for creating relative movement between thespindles and the work holders, a'main drive shaft, driving connectionbetween said shaft and the tool carrying spindles, the drivingconnection between one of the spindles and the drive shaft comprisingtwo sets of pulleys for reverse driving, and a belt shiftable from oneto the other of said sets, driving connections between the main driveshaft and the vertical shaft, a cam shaft, driving connections betweenthe cam shaft and the vertical shaft, a shifting. lever engaging theaforesaid belt, and a cam on the. cam shaft for'actuating said lever.

9. In a machine of the character set forth, the combination of asupporting structure, a turret movably sustained thereby, work holderscarried by said turret, tools supported by the structure in operativerelation tothe work holders, means for creating relative movementbetween the tools and work holders, a main drive shaft, drivingconnections between said shaft and the various tools, drivingconnectionsbetween the turret and the'main drive'shaft, a lockingibolt for theturret, a cam shaft supported by the structure, drivingconnectionsbetween the maindrive Sllfifllufil'ld the cam'shafhand a: cam' carriedby' the camshaft for operating the turret locking bolt.

'10. In a machine ofthe character set forth, the combination of asupporting structure, a turret movably sustained thereby, work holderscarried by said turret,1tools support'ed'by the structure in operativerelation to the Work holders, means fon creating relative movementbetween the tools and Work, holders, a main drive shaft, drivingconnections between said shaftwand the variousv tools,drivingconnections between the turret and the main drive shaft, meansfor advancing one-of the tools towards theworkv sustained by theholders: and including a push rod, a. cam shaft supported by thestructure, driving: connections between the Tao mainv driveshaft and?the cam shaft, and a cam carried by the cam shaft; for" operating theaforesaid pushi rod. r

11.'In a machine of the character set forth, the combination of asupporting structure,.an' annular turret-movably sustained thereby, ashaft supported vertically by said structure and centrally ofthe'turret, worka holders carried by the turret, tool carryingspindle's-journaled; within the structure, the spindles and workholders'being capable of relative movement, a cam engaging memberassociated with each spindle for creating relative movement between itand'a work holder, the members'associated with the various; spindlesoccupying diflerentplanes, a plurality of. cams. carriedby the aforesaidshaft, oneiin the plane. of and for engagement with. each oftheafbresaidcam engaging members, driving-means for the spindles, and drivingmeans'for the aforesaid shaft.

12. In a: machine: of. the character set forth, the combination ofasupportingstructure, a turret movably sustained: thereby,

work holders carried by the turret; a shaft supported by thestructurein;a vertical: position and centrally of the turret, toolcarryingspindlessupported by the structure,

cams carried by the vertical. shaft for, creating, relativemovement-between the spindles and the workholders, driving means: for

the spindles, and driving mcansfor the vertical shaft. Y

13. In a machine of the character set forth, the combination of asupporting structure; a turret movably sustained thereby Work ld scarried by the turret, a

shaft supported by the structure in a vertical position and centrally ofthe turret,

tool. carrying spindles supported by the ing spindles supported by thestructure,

cams carried by the vertical shaft for create ing relative movementbetween the spindles and the work holders, and driving mechanism=havingoperativeconnection with the spindles, the vertical shaft, and theturret, a clutch incorporated in the connections be tween the drivingmechanism and the turret,

and a'cam' included; in the mechanism for actuating the clutch; r V

v 15. In a machine of the character set forth, the. combination of asupporting structure, a turret movably sustained thereby, work hold:-

ers carried by the turret, a; shaft supported by thestructure in avertical; position and centrally of the turret, tool carrying spindlessupportetbby the structure, cams carried 7 by the vertical shaft forcreating; relative movement between the spindles and theworlc holders,driving mechanism, operative connections betweensthe driving mechanismand the-spindles, connections between one of the spindles and the:driving mechanism incorporatingreversmg means, means included 1n thedriving mechanism for actuating the reversing' means, and driving meansfor the vertical shaft; 1 1

16'. In-amachine of the character set forth, the: combination ofa'supporting structure,

a turret movably sustained thereby,- work Q holders carried. by saidturret, toolssup';

ported by the structure in operative rela tion to the, workholders-,means for creating relative movement between the tools and workholders, drivingmechanism, operative connection: between the drivingmechanism andwthe turret: for imparting; intermittent movementto: theturret, means for locking the turret, meansactuatedby the drivingmechanism. for operating the locking means,

and means for driving the tools. g 17. In a machine of. the characterset forth the combinationof a supporting structure, a turret movablysustained thereby, work holders carried by said turret, tools supportedby the structure in operative relation to the work holders, means forcreating relative movement between the tools and work holders, a maindrive shaft, driving connections between said shaft and the varioustools, driving connections between the turret and the main drive shaft,certain of the aforesaid means including a push rod for advancing thework toward a tool stationarily supported by the structure, a cam shaftsupported by the structure, driving connections between the main driveshaft and the cam shaft, and a cam carried by the cam shaft foroperating the aforesaid push rod.

18. In a machine of the character set forth, the combination of asupporting structure, a turret 'rotatably supported thereby and havingradial grooves, work holders guided within said grooves, and anactuating element situated centrally of the turret for moving the workholders radially of the turret.

.19. In a machine of the character set forth, the combination of asupporting strucwork holders shiftable radially of the turret, anactuator disposed centrally of the turret for moving the work holdersoutwardly, means for rotating the turret, and passive means situatedbeyond the periphery of the turret for moving the work holders inwardlyas the turret is rotated.

20. In a machine of the character set forth, the combination of asupporting structure, a turret rotatably supported thereby, an actuatorsituated within the outline of the turret, and work holders carried bythe turret and shiftable by the actuator toward the periphery of theturret.

21. In a machine of the character set forth, the combination ofasupporting structure, a turret rotatably supported thereby, an actuatorsituated within the outline of the turret, work holders carried by theturret and shiftable by the actuator toward the periphery of the turret,and passive means situated beyond the periphery of the turret for movingthe work holders inwardly as the turret is rotated.

In testimony whereof, I hereunto affix my signature.

NATHAN F. FRETTER.

cmmcae or Coi'rpctfun.

It is hereby certified-that in Letters Patent NcL- '1,408,997,'granedMarch 7. 1922, upon the applieation of Nathan F. Fretter, of Cleveland,Ollie, for an improvement in Lathes, ere-ore appear in the specificationrequiring correction as follows: Pages 4 aid 5, line 127 of olefin 11ndlinens of claim 2, strike out the-vyon i diesimilafl; andf-that thesaid' Letters Patent should be read with these correefime therein thatthe same may conform t0 the recegd of the casein the Patent Office. v

si ned'md sealed this. mi do} of April, 4A)., 1 22.

1mm I KARL FENNING,

Ac'thwcbmmiuioner 9}: Patents.

